Blast media nozzle and nozzle assembly

ABSTRACT

A novel blast nozzle and nozzle apparatus are provided to eliminate time and tooling requirements of prior art blast nozzles. The nozzle is utilizable with a union connector, which includes a connector body having an axial bore and a boss centrally disposed within the bore. The connector also has a collet seated within the bore that includes gripping teeth. The teeth are oriented inwardly toward the boss and are positioned at an engagement distance from the boss. The nozzle includes a nozzle body with an inlet end and an axial bore. The nozzle also includes a capture band that is positioned about the nozzle body at approximately the engagement distance from the inlet end. The capture band is sized and configured to substantially engage the gripping teeth of the collet to restrict axial movement of the nozzle upon insertion into the connector.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT

Not Applicable

BACKGROUND

The following generally relates to abrasive blasting and, morespecifically, to a uniquely designed blast nozzle and nozzle assemblythat eliminates the need for standard tooling typically required toinstall and replace blast nozzles.

Abrasive blasting processes are widely used to remove unwanted materialsfrom a substrate surface. In most cases, compressed air or other fluidis applied to propel abrasive particles such as sand, ceramic alumina,tungsten carbide, boron carbide, or silicon nitride through a conduit,against the substrate surface. Through a nozzle, the abrasive materialsare accelerated to a high speed and collide with a target surface. Thecollisions force removes unwanted dirt or other materials away from thetarget surface.

The blast nozzle itself is a major element determining the effectivenessof a blasting apparatus. Typically, the blasting apparatus includes anair hose, an abrasive hose, a gun, and the nozzle. The air hose and theabrasive hose are connected to the gun and supply compressed air (orfluid) and an amount of abrasive particulate, respectively, to the gunwhere the air is utilized to accelerate the abrasive particulate to highspeeds for blasting. The acceleration of the abrasive particulate occursprincipally in the nozzle, and principally due to the configuration ofthe nozzle. The nozzle used in abrasive blasting includes an entrancebore through which compressed air/fluid carrying abrasive particlespasses. The entrance bore of the nozzle typically converges over arelatively short distance into a smaller-diameter exit bore. The quicklydecreasing cross-sectional area of the converging section of the nozzleaccelerates the abrasive particles. Such acceleration allows theabrasive materials to exit the nozzle and bombard the target surface atelevated speeds for more efficient cleaning.

The pressure within the gun due to the compressed air/fluid, whichfrequently reaches 100 psi, creates tremendous forces on the nozzleduring the blasting process. Consequently, the nozzle must be firmlymounted to the gun. Otherwise, the forces behind the nozzle may causethe nozzle to be ejected from the gun at extremely high speeds, akin tothe action of a bullet from a gun. Manufacturers have made certaindesign changes to the nozzles in order to prevent such mishaps andaccidents. For example, as shown in FIGS. 1 a and 1 b, a common designfor a nozzle 10 includes a threaded engagement portion, which threadablyattaches the nozzle 10 to the blast gun. The threaded engagement portion12 allows the nozzle 10 to be threaded into position and fastenedtightly to the gun. The threaded nozzle 10 is usually attached to thegun by utilizing tools and other equipment such as ferrules, wrenches,and the like. However, the nozzle 10 must be installed on the gun withgreat care and effort. This laborious process of installing the nozzletypically requires the tightening of at least two ferrules and cautioushandling of the wrench so as to preserve the nozzle intact.

Although the inclusion of a threaded engagement portion on prior artnozzles has been quite successful in ensuring that the nozzles do notbecome projectiles during blasting operations, there are certaindisadvantages associated with the required installation procedures andthe inclusion of threads on the gun. As alluded to above, installationof a threaded nozzle requires several steps, including the tighteningand attachment of ferrules. This process is sometimes made difficult dueto the residue of abrasive particulate that may be present in the femalenozzle attachment threads of the gun. This simple problem is a burdenduring installation because it creates a cleaning step. As a result, theinstallation of the nozzle may take several minutes, if not createadditional problems due to improper installation technique or handlingof the nozzle during installation.

The above-mentioned nozzle installation process has several inherentdrawbacks including the requirement of the use of tools, lost time forthe worker, and the increased risk of other, albeit less-foreseeableproblems during installation. Therefore, although threaded nozzles havebeen effective in ensuring the safe use of nozzles at high pressures,there is a need to improve the installation procedure of such nozzles.Indeed, there is thus a substantial need to provide an improved nozzleand nozzle assembly that eliminates the requirement of tools, ferrules,and other impediments in safely securing the nozzle to the blastingapparatus. There is a further need in the art for an improved nozzledesign that can be easily implemented on all sizes and shapes ofnozzles, as well as being compatible with all of the standard sizes andshapes of hoses, connectors, and guns. Finally, there is a substantialneed in the art for improving the speed, facility, and costeffectiveness of using blast nozzles for sand blasting and relatedapplications.

BRIEF SUMMARY

As mentioned above, an object of the present invention is to provide anozzle and a nozzle assembly that substantially reduces time and toolingrequirements for blasting operations. In particular, embodiments of thepresent invention serve to reduce the time and tooling requirementsnecessary to change or install the nozzle of a blasting gun.Additionally, embodiments of the present invention are operative toimprove the manner in which the nozzle is held by a blasting gun. Inthis regard, the substantial improvements and contributions to the stateof the art as disclosed herein, are believed to make the installationand mounting of the nozzle faster and simpler while maintaining acoupling that is as safe and effective as that of prior art threadedblast nozzles.

In an embodiment of the present invention, the nozzle assembly includesa union connector and the nozzle. The union connector includes aconnector body having an axial bore and a boss. The boss is centrallydisposed within the axial bore. The union connector also includes colletthat is at least partially seated within the bore and located at adistal end of the connector. The collet includes a plurality of grippingteeth oriented inwardly toward the boss, and the teeth are positioned atan engagement distance from the boss.

The nozzle is uniquely configured to be mounted within the unionconnector in order to ensure safe use of the nozzle, i.e., to ensurethat the nozzle does not become a projectile upon use. The nozzleincludes a cylindrical nozzle body that defines an inlet end. The nozzlealso includes an axial bore through which abrasive particulate travelduring the blasting operation. Further, the nozzle includes a captureband that is positioned about the nozzle body at approximately theengagement distance from the inlet end. The capture band is sized andconfigured to substantially engage the gripping teeth of the collet whenthe nozzle is inserted into the union connector. The engagement of thecapture band with the gripping teeth serves to restrict axial movementof the nozzle, thereby maintaining the nozzle secured within the unionconnector.

As mentioned, the engagement of the capture band to the gripping teethoccurs when the nozzle is inserted into the connector. Preferably,engagement occurs as the inlet end of the nozzle converges upon the bossof the connector so as to ensure a tight fit between the nozzle and theunion connector. Engagement of the capture band to the gripping teethmay thus non-removably mount the nozzle to the connector.

The capture band of the nozzle may be variously configured. According toan implementation of the present invention, the capture band may atleast in part, define a groove. For example, the capture band may be anannular groove that is position proximate the inlet end on the nozzlebody. The groove may also be planar. Further, the annular groove maydefine a rectangular cross section. However, it is also contemplatedthat the capture band may also be a raised area along the nozzle bodywhich would similarly cause engagement with the gripping teeth.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the various embodimentsdisclosed herein will be better understood with respect to the followingdescription and drawings, in which like numbers refer to like partsthroughout, and in which:

FIG. 1 a is a perspective view of a prior art blast nozzle including athreaded engagement portion;

FIG. 1 b is a cross-sectional view of the prior art blast nozzle showinga threaded engagement portion;

FIG. 2 a is a perspective view of a nozzle in accordance with anembodiment of the present invention;

FIG. 2 b is a cross-sectional view of the nozzle including a captureband, shown as a groove, in accordance with an implementation of thepresent invention;

FIG. 3 is a side view of a nozzle assembly including a union connectorand the nozzle in accordance with another embodiment of the presentinvention; and

FIG. 4 is a cross-sectional view of the nozzle assembly illustrating theengagement of gripping teeth of the union connector with the captureband of the nozzle.

DETAILED DESCRIPTION

Referring now to the drawings wherein the showings are for purposes ofillustrating a preferred embodiment of the invention only, and not forpurposes of limiting the same, FIG. 2 a is a perspective view of anozzle 100 in accordance with an embodiment of the present invention. Asmentioned above, nozzles are typically used in a variety ofapplications. Embodiments of the present invention may be mounted inblasting guns used in blasting operations to accelerate a fluid orparticulate in order to blast a substrate. This process causes a greatamount of pressure and force to be exerted on the nozzle 100 due to thefluid being urged therethrough. As described above, in order to ensurethat a nozzle does not shoot out of the blasting gun, prior art deviceshave used hardware such as ferrules and required the use of other toolsto mount or remove a prior art nozzle 10. In contrast, embodiments ofthe present invention include a capture band 102 disposed on the nozzle100 that is designed to engage gripping teeth 104 of a connector 106 andthereby secure the nozzle 100 thereto. As will be seen, embodiments ofthe present invention allow a user to quickly install and safely use thenozzle 100, thus eliminating the tooling and equipment requirements ofthe prior art. These advantages, as well as others, over the prior artare due to the unique features of the present invention, discussedfurther below.

The nozzle 100 is used in conjunction with the connector 106, andpreferably used with a union connector 108, as illustratively shown inFIGS. 3 and 4. Other types of connectors 106 may be utilized to securethe nozzle 100 for use. However, the union connector 108 is preferablebecause of its versatility to be used with various sizes of pneumatichose 110. The connector 106 may accommodate the standard hose 110 andnozzle 100 diameter sizes, such as ⅛ inch, ¼ inch, ⅜ inch, ½ inch. Theconnector 106 must be operative to fluidly interconnect the hose 110 tothe nozzle 100, wherethrough a fluid or abrasive particles may travel.For example, in abrasive blasting, the connector 106 would fluidlyinterconnect the hose 110 to the nozzle 100 in order to direct an outputstream from the hose 110 toward a target object.

The connector 106 is preferably configured to include a connector body112 and a collet 114. The connector body 112 includes an axial bore 116and a boss 118 which is centrally disposed within the axial bore 116.The collet 114 of the connector 106 is at least partially seated withinthe bore at a distal end 120 of the connector 106. Finally, the collet114 includes a plurality of gripping teeth 104 oriented inwardly towardthe boss 118. The teeth are positioned at an engagement distance 122from the boss 118. Other configurations and various equivalents for thecollet 114 and the gripping teeth 104 may be designed and may bepresently available in the art. These, and other features of theconnector 106 may be variously modified and adapted to be utilized withembodiments of the present invention. The connector 106 may also be madeof various materials as known in the art.

As show in FIG. 2 b, the nozzle 100 may be a straight nozzle 100 with aventuri 124 that converges to an axial bore 126. However, the nozzle 100is not limited to a particular internal configuration, but may beconfigured to include single or double venturis 124 of various lengths,angled blast outputs of various configurations and number, waterinduction, siphons, and various blast patterns configurations, to name afew. Additionally, as will be noted through the teachings herein, thenozzle 100 may be manufactured of various materials such as tungstencarbide, aluminum oxide, boron carbide, silicon carbide, and various newmaterials such as that manufactured by Cerbide™.

Referring now to FIGS. 2 a and 2 b, the nozzle 100 includes a nozzlebody 128 defining an inlet end 130 and including the axial bore 126. Thenozzle body 128 may be variously configured, such as to be cylindrical,which configuration is generally used in the industry. However, otherconfigurations of the nozzle body 128 may be developed and utilized. Thenozzle 100 may thus be variously configured to include features that mayaffect the size, shape, and geometry of the axial bore 126.

The capture band 102 of the nozzle 100 is positioned about the nozzlebody 128. The band is sized and configured to substantially engage thegripping teeth 104 of the collet 114 to restrict axial movement of thenozzle 100 upon insertion into the connector 106. The engagement of thecapture band 102 to the gripping teeth 104 may occur during insertion ofthe nozzle 100 into the connector 106 as the inlet end 130 of the nozzle100 converges upon the boss 118 of the connector 106. Additionally, thenozzle 100 may need to be rotated or moved within the connector 106 inorder to complete the engagement or to adjust and verify the engagementprior to use.

One of the primary beneficial features of the embodiments of the presentinvention lies in the fact that the engagement may be accomplishedwithout the use of tools. In addition, the engagement allows the nozzle100 to remain mounted in the connector 106 during use, instead of beingtransformed into an unsafe, high-speed projectile once the pressure fromthe abrasive fluid is applied. In this regard, the nozzle 100 may benon-removably engaged to the connector 106 for axial forces exerted bythe fluid that are slightly greater than the maximum pressure of theconnector 106. As is known in the art, the connector 106 may be capableof handling a certain maximum pressure. It is contemplated that theengagement of the nozzle 100 may be able to withstand the maximumpressure force that the connector 106 can withstand without beingdischarged from the inlet end 130 of the connector 106. This will ensurethat if the connector 106 is used according to its safety standards andratings, the nozzle 100 will also be safely engaged by the connector106. Thus, according to preferred embodiments, the nozzle 100 isnon-removably engaged to the connector 106 once proper engagementbetween the teeth 104 and the capture band 102 has been made.

The nozzle 100 may be sold together with a proper connector 106 as anozzle assembly 134, although they may also be sold separately. Althoughpictured with a length of hose 112, it will be understood that thenozzle assembly 134 may simply include the nozzle 100 and the connector106. Because the nozzle 100 will eventually be disposed of when itreaches its services life, and because the connector 106 is relativelyinexpensive, the connector 106 may be disposed of along with the nozzle100 when the nozzle 100 reaches its service life.

The engagement of the capture band 102 and the gripping teeth 104 is duein part to the orientation of the teeth 104 of the connector 106, whichmay be oriented inwardly both axially and toward the boss 118, as shownin FIGS. 3 and 4. The teeth 104 are preferably angularly oriented withrespect to the nozzle body 128. In other words, the teeth 104 maypreferably be configured to converge toward the capture band 102 of theinserted nozzle 100, also converging inwardly toward the boss 118 of theconnector 106. The gripping teeth 104 are operative to dig into softermaterial types, such as a rubber pneumatic hose 110. However, becausethe nozzle 100 may typically be made of a very hard material, thecapture band 102 is required to ensure that the gripping teeth 104 areable to properly engage the nozzle 100 to prevent axial movement.Various teeth configurations may be utilized and may correspond to thedimensions and configuration of the capture band 102 of the nozzle 100,and vice versa.

Further, although possibly less preferable, the nozzle 100 mayalternatively be configured to include a sleeve being made of a materialthat is soft enough to be properly engaged (dug into) by the grippingteeth 104. However, in such a situation, the nozzle 100 would only beindirectly engaged within the connector 106. Thus, the incorporation ofthe sleeve may be problematic because it must be fixedly secured to thenozzle 100 utilizing an adhesive or structural component. Nevertheless,it is contemplated that the engagement of the nozzle 100 with thegripping teeth 104 may include such indirect forms of engagement.

Once the teeth 104 are engaged with the capture band 102, an axial forcedirected to remove the nozzle 100 from the connector 106 causes theteeth 104 of the collet 114 to dig or be thrust further into the captureband 102, thereby impeding removal of the nozzle 100. In a typical use,this axial force may be supplied by the axial force created by fluidbeing urged through the connector 106 and out through the nozzle 100,and attempting manual removal of the nozzle 100 from the connector 106may require similar axial forces. The engagement of the capture band 102with the teeth 104 is strong enough to counterbalance the axial forceson the nozzle 100. As mentioned above, the nozzle 100 may benon-removably engaged by the gripping teeth 104 when the forces of thefluid are applied thereto.

In accordance with an embodiment of the present invention, the captureband 102 preferably encircles the entire nozzle body 128 in acircumferential manner, as shown in FIGS. 2 a and 2 b. The capture band102 may be continuous or discontinuous, and may also be raised orindented, as discussed below. The capture band 102 may therefore beannular and is preferably a continuous band. For example, as also shownin FIGS. 2 a and 2 b, the capture band 102 may be a groove 132 thatcircumferentially covers the nozzle body 128. In this regard, the groove132 may be configured to define a rectangular cross section, as shown inFIGS. 2 a, 3, and 4. The cross-section of the capture band 102 may alsobe modified to correspond to the gripping teeth 104 of the collet. Asmentioned, the teeth 104 may dig or be thrust into or toward the captureband 102. Thus, the teeth 104 may be lodged to within the groove 132.The teeth 104 may also be forced against other portions of the groove132, such as edges or boundaries of the groove 132. Therefore, the teeth104 may be axially compressed against the groove 132 or may also providea longitudinal impediment to axial movement.

The groove 132 may also be variously configured. For example, if thecollet 114 includes only three gripping teeth 104, the capture band 102may be configured to include three notches wherein the three teeth 104may be seated upon engagement. Further, if the teeth 104 are configuredto include a specific pattern or design at their distal end 120, thecapture band 102 may be designed to lock the distal ends 120 of theteeth 104 therein in order to complete engagement. The groove 132 mayalso be planar. In such an embodiment, groove 132 may define a plane andthe nozzle 100 may define a central axis. The plane may be perpendicularto the central axis of the nozzle 100, and the groove 132 may beparallel to the plane. This embodiment is illustrated in FIGS. 2 a and 2b. However, the groove 132 may also be shaped as a zig-zag pattern,offset rings, or multiple indentations. Thus, although the groove 132may not be a continuous slot about the nozzle body 128, the groove 132may provide a discrete number of indentations suitably sized andconfigured to receive the gripping teeth 104 for engagement. Further,the groove 132 may be other than rectangular in its cross sectionalgeometry. For example, the groove 132 may be configured similarly to aparallelogram to correspond to the shape of the gripping teeth 104. Suchconfiguration may allow the gripping teeth 104 to be axially slidablyreceivable within the groove 132. However, a slidable engagement betweenthe nozzle 100 and the connector 106 should be configured to ensure thatany gap between the inlet end 130 of the nozzle 100 and the boss 118 ofthe connector 106 is minimized, as described below, so as to protectagainst blowing the connector 106. Additionally, the groove 132 may alsobe configured to provide other forms of engagement such as by twistingthe nozzle 100.

According to another embodiment of the present invention, the captureband 102 may also be configured as a raised portion of the nozzle body128, such as a protrusion or a bump. In such an embodiment, engagementpreferably occurs when the capture band 102 is axially forced past theteeth 104 upon insertion of the nozzle 100 into the connector 106.Although not shown, a continuous or discontinuous protrusion about thenozzle body 128 may also serve to provide the engagement with thegripping teeth 104, as similarly described above in relation to thegroove 132. In such an embodiment, the protrusion is preferablycontinuous about the nozzle body 128, such as a continuous raised rib.In use, when the teeth 104 engage the capture band 102, and the axialforce directed to remove the nozzle 100 from the connector 106 isexerted, the teeth 104 dig into or are thrust into the raised rib andthus impede removal by tending to limit axial movement of the nozzle100. The exertion of these forces may result in axial compression of thecapture band/raised rib 102 by the teeth 104. Alternatively however, theraised rib may be sufficient to restrict the axial movement of thenozzle 100 because the teeth 104 block passage of the captureband/raised rib 102.

Furthermore, the capture band 102 may be configured to include both thegroove 132 and the raised portion. With such a combination, varioustypes of engagements between the nozzle 100 and the gripping teeth 104are possible. The slidable and twisting engagement may be performedutilizing the groove 132 and the raised portion.

In addition, the capture band 102 is preferably disposed atapproximately the engagement distance 122 from the inlet end 130 of thenozzle 100. Due to the forces exerted on the connector 106 byaccelerated fluid or abrasive particles, proper seating of the nozzle100 within the connector 106 is extremely important to ensure properengagement. The nozzle 100 should preferably be seated within theconnector 106 with the inlet end 130 of the nozzle 100 substantiallyabutting the boss 118 of the connector 106. If a gap remains between theinlet end 130 of the nozzle 100 and the boss 118 of the connector 106,the forces exerted by the fluid may blow the connector 106, which isextremely dangerous. The connector 106 may also be blown if the hose 110is cut crooked, i.e., not cut perpendicularly aligned to the axis of thehose 110. Thus, in order to ensure proper engagement of the nozzle 100,the capture band 102 is preferably spaced from the inlet end 130 of thenozzle 100 at the same distance from which the teeth 104 are disposedfrom the boss 118 of the connector 106, referred to herein as theengagement distance 122. The engagement distance 122 may be adjusted tocompensate for peculiarities in the engagement of the teeth 104 with thecapture band 102, such as for the geometry of the teeth 104 and captureband 102. It is contemplated that various alternative embodiments of theteeth 104 and/or capture band 102 may require specific attention todetermine the engagement distance 122 in order to ensure that the nozzle100 is properly seated in the connector 106.

The above description is given by way of example, and not limitation.Given the above disclosure, one skilled in the art could devisevariations that are within the scope of the invention disclosed herein,including various ways of manufacturing and utilizing the nozzle 100 andnozzle assembly 134. Further, the various features of the embodimentsdisclosed herein can be used alone, or in varying combinations with eachother and are not intended to be limited to the specific combinationdescribed herein. Thus, the scope of the claims is not to be limited bythe illustrated embodiments.

1. A nozzle for use with a connector, the connector including aconnector body and a collet, the connector body including an axial boreand a boss, the boss being centrally disposed within the axial bore, thecollet being at least partially seated within the bore at a distal endof the connector, the collet including a plurality of gripping teethoriented inwardly toward the boss, the teeth being positioned at anengagement distance from the boss, the nozzle comprising: a nozzle bodydefining an inlet end and including an axial bore; and a capture bandbeing positioned about the nozzle body at approximately the engagementdistance from the inlet end, the band being sized and configured tosubstantially engage the gripping teeth of the collet to restrict axialmovement of the nozzle upon insertion into the connector.
 2. The nozzleof claim 1 wherein engagement of the capture band to the gripping teethoccurs during insertion of the nozzle into the connector as the inletend of the nozzle converges upon the boss of the connector.
 3. Thenozzle of claim 1 wherein engagement of the capture band to the grippingteeth non-removably mounts the nozzle to the connector.
 4. The nozzle ofclaim 1 wherein the capture band defines a groove.
 5. The nozzle ofclaim 1 wherein the capture band is an annular groove on the nozzlebody.
 6. The nozzle of claim 5 wherein the annular groove defines arectangular cross section.
 7. The nozzle assembly of claim 1 wherein thecapture band is substantially planar.
 8. A nozzle for use with a unionconnector, the union connector including a connector body and a collet,the connector body including an axial bore and a boss, the boss beingcentrally disposed within the axial bore, the collet being at leastpartially seated within the bore at a distal end of the connector, thecollet including a plurality of gripping teeth oriented inwardly towardthe boss, the nozzle comprising: a cylindrical nozzle body defining aninlet end and including an axial bore; and a capture groove beingpositioned about the nozzle body proximate the inlet end, the groovebeing sized and configured to substantially receive the gripping teethof the collet upon insertion of the nozzle into the distal end of theconnector to restrict axial movement of the nozzle.
 9. The nozzle ofclaim 8 wherein the gripping teeth of the collet are positioned at anengagement distance from the boss of the connector, the groove beingdisposed at approximately the engagement distance from the inlet end tofacilitate engagement of the gripping teeth of the collet with thegroove of the nozzle.
 10. The nozzle of claim 8 wherein engagement ofthe capture band to the gripping teeth non-removably mounts the nozzleto the connector.
 11. The nozzle of claim 8 wherein the groove has arectangular cross section.
 12. The nozzle of claim 8 wherein the grooveis substantially planar.
 13. The nozzle of claim 8 wherein the groove isannular.
 14. A nozzle assembly, the assembly comprising: a unionconnector including: a connector body including an axial bore and aboss, the boss being centrally disposed within the axial bore; and acollet being at least partially seated within the bore at a distal endof the connector, the collet including a plurality of gripping teethoriented inwardly toward the boss, the teeth being positioned at anengagement distance from the boss; and a nozzle including: a cylindricalnozzle body defining an inlet end and including an axial bore; and acapture band being positioned about the nozzle body at approximately theengagement distance from the inlet end, the band being sized andconfigured to substantially engage the gripping teeth of the collet torestrict axial movement of the nozzle upon insertion into the connector.15. The nozzle assembly of claim 14 wherein engagement of the captureband to the gripping teeth occurs during insertion of the nozzle intothe connector as the inlet end of the nozzle converges upon the boss ofthe connector.
 16. The nozzle assembly of claim 14 wherein engagement ofthe capture band to the gripping teeth non-removably mounts the nozzleto the connector.
 17. The nozzle assembly of claim 14 wherein thecapture band defines a groove.
 18. The nozzle assembly of claim 14wherein the capture band is an annular groove on the nozzle body. 19.The nozzle assembly of claim 18 wherein the annular groove defines arectangular cross section.
 20. The nozzle assembly of claim 14 whereinthe capture band is substantially planar.